But we often take the male orgasm for granted (or… maybe not, at this stage of the game). For most of us—at least in the beginning, that pump was always primed; the shotgun always loaded. Now, whether our partner is slowing down, in need of a little pharma assistance, or still willing and able at the drop of a pin, we know for certain that his orgasmic experience is different from ours.

For starters, its purpose is different; the plumbing is different; and the “sexual-response cycle” (a term coined by sex researchers Masters and Johnson) has a different timing (say, like a hair-trigger).

On the other hand, male and female orgasms do share basic similarities in that both genders progress through similar stages. And, as with its female counterpart, a lot is still unknown about the male orgasm.

Since a little knowledge is a helpful thing, understanding what happens during a guy’s orgasm might help us appreciate the similarities and differences of our mutual experience. Maybe Mars and Venus can orbit in slightly greater harmony.

The male orgasm is designed to position healthy, active sperm so that it achieves its biological objective—babymaking. The job involves the coordination of brain, nerve, muscle, and blood, and psychological factors, to get those swimmers into our receptive vessel.

Testosterone is the juice that fuels the system in a male. It’s the critical hormone that keeps his libido finely tuned and his sexual apparatus running properly. Testosterone can boost our libido too, but a guy’s daily testosterone output is about 20 times greater than ours.

Testosterone is produced in the testicles, which also makes the sperm and mixes it with a protein-rich fluid bath for nourishment during the arduous trip up the vagina. Sperm and fluid together constitute semen, which is what is ejaculated during orgasm.

Usually (there are some exceptions), a guy has to have an orgasm for the pumping mechanism to work. For us, orgasm is nice to have, but not essential to the job at hand. Our orgasm might help those little sperms along somewhat, and it makes sex feel good, but orgasm or no, we can still get pregnant.

The actual sexual-response cycle unfolds in four stages for both men and women. For a guy, however, orgasm is a more straightforward and less tricky process. Given a normal anatomy and normal testosterone levels, a flash of nicely turned thigh or bosom is enough to trigger the first stage of the male orgasm: arousal.

We experience arousal too, of course, but it generally takes different stimuli and a longer time frame.

During arousal, blood flows into a guy’s penis through enlarged arteries perhaps 50 times faster than normal, and veins that normally drain blood from the penis close off. Muscles tense and the scrotum pulls inward.

Voilà! Erection.

The second stage is the plateau, in which the man’s body prepares for orgasm. Heartrate and blood pressure increase. Muscles tense further. Involuntary pelvic motions begin. A clear pre-ejaculate fluid may change the PH balance in the urethra so the sperm has a better chance of survival.

Orgasm in men occurs in two phases. First, semen collects in the urethral bulb at the top of the penis. This is called “ejaculatory inevitability,” in which the man reaches the point of no return. Then, the rockets fire. Muscles at the base of the anus contract rapidly to pump semen through the urethra, and nerves deliver orgasmically pleasurable messages to the brain. The ejaculation phase is fairly reflexive and is controlled by nerves in the spinal column.

The final stage—resolution— is when our man rolls over and falls asleep and we’re left feeling all warm and fuzzy and yearning for pillow talk—or for more sex. But don’t jump to conclusions—he’s spent, literally. He loses about half his erection immediately; the rest fades shortly.

While we may not be fully satisfied after one orgasm, our man is. It takes a recovery period (called refraction) before he’s ready to go again. When he was 19, refraction may have lasted half an hour. Now, well, it’s a different story. This is when a little sleight of hand or toy action might help you out.

While the male orgasm is less affected by mood and psychological factors than ours, hormonal imbalances, physical issues, medications, and of course, aging can still muck up a man’s ability to become aroused or to have an orgasm.

So, the next time your man starts to snore as soon as the deed is done, you don’t need to take it personally. Blame nature.